Siobhan Mckenna, 63, Movie, Stage Actress

DUBLIN, IRELAND — Irish actress SIOBHAN MCKENNA, 63, known for the roles of tragic heroines that she played for more than four decades, died Sunday of a heart attack.

Cyril Cusack, the 75-year-old Irish actor now based in London, called her death ''a great shock and a great loss to the Irish theater and the country.''

A vibrant actress, McKenna performed on stage and in movies in the British Isles and the United States, but she was most widely known for her stage work in Dublin. She made her stage debut in 1940 in Ireland and cemented her reputation in England acting as the martyred Joan of Arc in a 1954 production of George Bernard Shaw's Saint Joan.

Broadway followed in 1955, where she starred opposite Gladys Cooper in Enid Bagnold's The Chalk Garden. Subsequent North American engagements included Saint Joan in Cambridge, Mass., and New York in 1956; Viola in Shakespeare's Twelfth Night at the Stratford Festival in Ontario in 1957; and the lead role in an off-Broadway production of Hamlet in 1957.

In 1959 she played Lady Macbeth opposite Jason Robards in a Cambridge production of Shakespeare's Macbeth.

Despite success abroad, McKenna always returned to Ireland to perform in classics and new plays. From 1960 on, she became a regular at the annual Dublin Theater Festival.

In London this year, she starred as the bedridden Mommo in Tom Murphy's Bailegangaire.

McKenna's film credits included Hungry Hill, King of Kings, a 1964 remake of Of Human Bondage, and Doctor Zhivago.